Project description:Whole transcriptome comparison of two mesenchymal GBM stem cell lines transfected with control vs fibulin-3 (EFEMP1) siRNAs. GBM stem cell lines GBM09 and GBM34 developed in-house from freshly-resected primary GBM tumors, using standard procecures (Galli et al.; Cancer Res (2002) 64:7011). Cells were transfected with two fibulin-3 or control siRNAs and collected 48h after transfection. Gene expression was quantified by RNAseq using standard procedures. The results suggest that downregulation of fibulin-3 affects NF-kB-dependent GBM gene signatures associated with angiogenesis and immunosuppression.
Project description:Whole transcriptome comparison of mesothelioma cells transfected with control vs Fibulin-3 (EFEMP1) siRNAs. Mesothelioma cells H-226 (ATCC) and H-2595 (Harvey Pass, New York University) were transfected with two fibulin-3 or control siRNAs and collected 48h after transfection. Gene expression was quantified by RNAseq using standard procedures. The results suggest that downregulation of fibulin-3 negatively affects a PI3K/AKT-dependent gene signature involved in cell growth, adhesion, and association with the extracellular matrix.
Project description:Glioblastoma is the most frequent type of adult-onset malignant brain tumors and has a very poor prognosis. A cell population called glioblastoma stem cells has been shown to be one of the mechanisms by which glioblastoma acquires therapy resistance. Therefore, there is a need to establish novel therapeutic strategies useful for inhibiting the cell population. γ-glutamylcyclotransferase (GGCT) is an enzyme involved in the synthesis and metabolism of glutathione, which is highly expressed in a wide range of cancer types including glioblastoma, and inhibition of its expression has been reported to have antitumor effects on various cancer types. In this study, we searched for pathways affected by the growth-promoting effect of GGCT overexpression in mouse embryonic fibroblasts NIH3T3 by comprehensive gene expression analysis and found the hedgehog pathway. Knockdown of GGCT inhibited proliferation of glioblastoma stem cells derived from a mouse glioblastoma model and caused decreased expression of desert hedgehog (Dhh), a representative ligand of the pathway, and the downstream target Gli1. To analyze the contribution of reduced Dhh, we activated the hedgehog pathway by forced expression of Dhh. We found that Dhh overexpression significantly restored the growth suppressive effect of GGCT knockdown. The results of this study indicate that high GGCT expression is important for Dhh expression and activation of the hedgehog pathway, which is required to maintain glioblastoma stem cell proliferation. Therefore, inhibition of GGCT function may be useful in suppressing stemness of glioblastoma stem cells accompanied with activation of the hedgehog pathway.
Project description:The extracellular matrix (ECM) plays a crucial role in building the extracellular environment and translating extracellular information into biochemical signals that sustain organ functions. Fibulin-5 is a multifunctional ECM protein essential for the formation of elastic fibers and the regulation of cellular functions through integrin binding. Fibulin-5 expression decreases with aging in human skin; however, its functional significance remains unknown. To address the roles of fibulin-5 in regulating epidermal stem cells during skin aging, Fbln5 knockout mice were examined for changes in their cellular and molecular phenotypes. Loss of Fbln5 in mice results in early impairments of epidermal stem cell properties, similar to the chronological aging of the skin. Fibulin-5 deficiency results in the suppression of integrins and other cell junctional molecules, leading to the inactivation of YAP signaling in epidermal stem cells. The reduced YAP signal is associated with the down-regulation of the fast-cycling epidermal stem cell marker, SLC1A3, in human skin and primary keratinocytes. These findings underscore the important role of fibulin-5 in governing the balance of epidermal stem cell populations during skin aging via crosstalk between the extracellular environment and intracellular signaling.